1. Technical Field
The present invention relates to an image projection apparatus, an image projection method, and a storage medium of a program of the image projection method, and more particularly to an image projection apparatus having an on-screen display capability.
2. Background Art
Image projection apparatuses known as projectors employing liquid crystal panels having improved resolution and light sources (e.g., lamps) having improved luminance are available with less expensive cost. For example, small and light-weight image projection apparatuses employing a digital micro-mirror device (DMD) are available. These image projection apparatuses are used in offices, schools, homes or the like.
The image projection apparatus can be connected with an image data providing apparatus such as a personal computer (PC). An image input to the image projection apparatus from the PC can be projected on a projection face such as a screen. Further, the image projection apparatus includes an on-screen display (OSD) capability that can superimpose a menu image on a projected image, wherein the menu image can be used to instruct various operations and settings to the image projection apparatus.
The menu image generated by the OSD capability can be used to set various settings such as language selection, display modes, image adjustment, and power source status. A user can request desired operations using the menu image. Further, a dialogue image and an error display image can be generated by the OSD capability. Hereinafter, the menu image, dialogue image, and error display image generate-able by the OSD capability may be referred to as an OSD image, an OSD, or a superimposition image.
Further, the image projection apparatus can include an image correction capability to correct input image signals or data before projecting images. FIGS. 20A and 20B are examples of image corrections performable by the image projection apparatus.
As illustrated in FIG. 20, an image correction can be performed to an input image 101. FIG. 20A is an example of zooming (e.g., reduction) for the input image 101, and FIG. 20B is an example of a trapezoid correction for the input image 101, in which an image display area (display area 103) for displaying an image is corrected for an entire projection image (entire area 102), and a partial area of the entire area 102 not used for the display area 103 is projected as a black area.
When the image correction is performed to change the image display area, display positions of an OSD image 104 can be fit within the corrected display area 103 as illustrated in FIGS. 21A, 21B, and 21C.
However, when a short-range focusing projector that projects images from a position close to a screen is used to project an image, tiny dents such convex and concave on the screen surface may cause a greater distortion. In this case, conventional correction methods that correct a trapezoid distortion of the entire image may not effectively correct the distortion.
In this case, a barrel correction can be performed to the input image 101 as illustrated in FIG. 22. The barrel correction means a correction of distortion in (−) direction known as pincushion distortion, and a correction of distortion in (+) direction known as barrel distortion as illustrated in FIG. 22. When the barrel correction is performed by conventional projectors, it is difficult to fit the OSD image 104 within the display area 103 of a corrected projection image. For example, as illustrated in FIG. 23, the OSD image 104 does it within the display area 103 but protrudes outside the display area 103.